Booster brake



Dec. 8, 192;:

` F. A. BOWER BOOSTER BRAKE Filed sept. 21. 1925 0 24a I *4 Z J1/Wenko@ 44 @www @Enma 33212* mi @Www/ms 7 z Z mw, 4%#

Patented De.8,1925.' y I ,f 12,564,515 UNITED STATES PATENT OFFICE.

FERDINAND A. BOWER,0F'FLIN T, MICHIGAN, ASSIGNORKTO GENERAL .MOTORS COR- PORATIN, F,DETROIT, MICHIGAN, A CORPORATION 0E DELAWARE.

Boosrnn BRAKE.

Application led September 21, 1923. Serial No. 664,067.

To all 'u1/om t may concern: c cam which expands a pair of internal shoes Be it known that I, FERDINAND A. BowER, lagainst the outer drum. This arrangement a citizen of the United States and aresiv` is one which I consider desirable for motor dent of Flint, county of Genesee,and State vehicles in that the entire brake is very 6 of Michigan, have invented certain new and compact and all of the parts are enclosed and 00 useful Improvements inBooster Brakes, of protected against dirt and oil.

. which the following isa full, clear, concise, The above and other objects and features and lexact descriptlon, such as will enable of the invention, includin various novel others skilled in the art to which the invcombinations of parts and esirable particu- 10 vention relates to make and use the same, lar constructions, will be apparent from the 05 referencey being made therein to the accomfollowing description ofthe illustrative empauying'drawlngs, which form a part of bodiment shown in the accompanying drawthis specification. lugs, 1n which:

' his invention relates to -boosterbrakesg igure 1 is a section on the line 1-1 of i'lli i. e. brakes ap lied by power which is Figure 2 showing the wheel and its axle and 70 manually contro led, and 1s illustrated as the improved brake 1n horizontal section; embodied in a brake of this character which and acts on the rear wheel of a motor vehicle. Figure 2 is a section on the line 2-2 of An object of the invention is to arrange Figure 1 showing the axle and brake drums 2o the parts of such a brake to secune a selfin vertical section and the other parts of 75 contained unit which may be substituted for the brake in side elevation. a brake of any other type without necessitatj In the particular embodiment selected for ing any changes in the operating connections lllustration the brake drums 1() and 12 are or 'in the vehicleitself. From this point carried by the rear wheel 14 of a motor of view the invention contemplates the use vehicle, which wheel is shown as having a 80 of inner and outer brake drums, which may full-floatmg mounting on the rear axle housbe rcarried by [the vehicle wheel and which ing 1.6 and as bv ing driven by the driving. are .shown as concentric'ally arranged one axle 18. Most of the parts of the brake Within the other in substantially the same and its connections are enclosed between the (plane, in combination with a pair of braking outer drum 10 and a stationary yplate 20 35' l evlces or equivalent retardiug means, one of supported on the housing 16. Certain parts .which devices is controlled by the driver of the brake' are si ported by a. stationary y and has a limited movement with its drum bracket or support a2 which may, if desired, l to apply the other device to the other drum be integral with the plate, but which is with a power which is a function of the shown as being a separate member; carried 904 power applied by the driver but which is by the housin' 16. l greatly in excess thereof. By this arrangei The inner rum 12l is arranged to be enment the brakes` are .as sensitive to the gagedl by a driven-controlled angularlydrivers control as,v the usual manually apmovable brakedevice shown in the form ofa plied brakes, while at the same time the ,-contractable band 24, the ends ofA which 05 driver is called onfor 'very much less et'- are connected to a rock member 26 keyed to a fort in ap lying thc brakes. l spindle 28 carried by a support or bracket Prefera ly the parts of the brake are eu- 30 which is mounted to have a limited anguclosed within the outer drum and a plate lar movement about the axis of the housing.

brakes are not materially different in ex- 32 in the plate 20, and is operated to a closlng its open end, so that the improved 16. The spindle 28 extends through a 10Q ternal appearance from an internalex andthe brakev by an arm 34 on its end w ich' ing brake of any conventional type. III); the is connected by a link S/tr tof connections arrangement shown in the drawings the con- Operatcd by the service brake pedal or the uections from the brake pedal or lever conf -emergency brake' lever or any equivalent 195 tract an external band about the inner drum, driver-controlled operating device. At its thc band moving'angularly a short distance opposite end the bracket 3 is provided with a s otted jaw 38 embracii r a pin 40 carried with its drum and turning its su port or bracket to rock an arm connecte to the by a rock arm 42 which is keyed t: a short 5 bracket by a pin-andvslot joint to turn a shaft 44 journaled in the plate 20 and the 110 support 22, and to vwhich is secured at ite opposite end a rock arm 46 connected by a link 48 with an arm 50, which is arranged to rock a shaft 52 journaled in the plate 20 and which carries a cam 54 operating to expand a pair of shoes 56 and 58 against the inside of the outer drum 10. The shoes 56 and 58 are shown as being pivotally connected at 60, and if desired the pivotal connections 60 may pass through the plate 20 to form a brake of the scissors type.

In. operation, depression of the brake pedal or manipulation of an equivalent controlling device by the driver rocks the member 26 to contract the band Q4 into trictional engagement with the \inner drum 12. Since the bracket. 30 is tre/0 to move, Within the limits detiiied by the arcuate slot 32 and uutil the friction of the band 24 againsttlie drinn l2 is balanced`by the resistance of cam ft to further turning movement, the band 24 will move with the drum 12 for a short distance, turning the support 30 about its axis. The slotted portion 38 'if the support 30 thus rocks the arm 42, operating through the arm 46 and the link 48 to rock the arm 50 and the cani 54 to expand the shoes 5G and 58 against the outer drum lO. The brakes niav be so adjusted that the braking ei'ort of tbe band 2l isBsinall as compared With the braking etl'ect ot' the shoes 5G and 58, inasmuch as the braking ei'ect of the band 2e is not balanced directly against that of the shoes 56 and 58 but is balanced `through power-multiplying leverage connections against tlie resistance ot' the cani 54 to turning movement. Thus a powerful braking action may be brought about by a coinparativcly small application of power by the driver; but this action is nevertheless a function of the power applied by *he driver, so that lie may graduate the braking effect accurately by varying the power which he himself applies.

While I have illustrated yand described one particular embodiment ot my invention, it is not my intention to limit its scope to that embodiment or Aotherwise than by the terms of the appended claims. The term drum throughout the specification and claims is intended as a convenient designation of a member 01"' any form having a motion which is to be retarded, except where this terni is in some Way specifically limited to a iar ticular form of drum.

l. claim:

l. A vehicle comprising, in combination, A wheel having inner and outer brake drums, a contractable external braking device en- 60 circling the inner drum, an expansible braking device within lthe outer drum and movable into frictions] engagement therewith, one of said devices having a limited movenient with its drum, driver controlled means for applying the movable braking device to 'its drum, and a connection ope-rated by movement thereof for applying the other braking device to thel other drum.

2. A vehicle comprising, in combination, a wheel having inner and outer brake drums, a cont-ractable band encircling the inner drum nd arranged to have a limited angular movement therewith, drivel` coutrolled means for contracting the band into frictional engagement with the drum, an eX- pansi'ble braking device arranged Within the outer drum, and a connection operated by angular movement of said band for expanding the braking device into rictionall engagement with the outer drum.

3. A vehicle comprising, in combination, a. Wheelhaving inner and outer brake drums, an angularly movable band contracta'le under the control ot' the driver into frictional engagement vvithlthe inner drum, expansible brake shoes arranged within the outer drum, a cam for expanding the shoes, and a oonnection operated by angular movement of the band for rocking the cam to expand the slices into frictional engagement with the outer drum.

il .sfr vehicle comprising, in combination, a Wheel having inner and outer brake drums, a Wheel support carrying an angularly movable bracket, a contractable band supported by the bracket and encircling the inner drinn, driver controlled means for contracting 'the band. a braking device operating on the outer drum, and a connection for applying the braking device to the outer drum including an arm having a pin-and-slot connection with the bracket to be operated'by angular movement thereof.-

5. A vehicle comprising, in combination, a wheel having inner and outer open ended brake drums, a stationarily supported plate substantially closing the open ends/oic the drums, an angularly movable supportI enclosed between the plate and the outer drum, a braking device carried by the angularly movable support, driver controlled /means for applying the device to the inner drum,l a braking device movable into irictional engagement with the outer drunnand connections operated by angular movement of the support *for moving the braking device againstlhe other drunnsaid connections including an arm mounted yoiithe late which has a. pin-and-slot connection Wit i the angularly movable support..

ln testimony whereof I aiiix'iny signature,

FERDNAND A. .50i/VER. 

